The National Parks Service is asking that no more cremated remains of service members, or anyone else for that matter, be left at the Vietnam Veterans Memorial Wall.

After the first cremated remains were left back in 1990, about 70 other containers of cremated remains have been left at the wall, park officials told the The Washington Post, noting that the remains of 31 people have been left over the past five years, including five in 2017.

According to a list maintained by the parks service, remains have been left in urns and in wood, glass, and metal containers. The remains of Daniel Dhee Hughes were left in a 155-mm artillery shell casing.

Cremated remain labeled for "Master Gunnery Sergeant Ronald William Looney," with the Marine Corps globe-and-anchor insignia with an ornate metal clasp, were left in a wooden box after he died in 2008, according to the Post.

The wall, located north of the Lincoln Memorial near the 22nd Street and Constitutional Avenue NW intersection, includes the names of more than 58,000 servicemen and women who died during the Vietnam conflict, which ended for the U.S. in 1973, according to the parks service website.

The memorial also includes "The Three Servicemen" statue and the Vietnam Women's Memorial.

People have left mementos at the Vietnam Memorial since the wall was dedicated in 1982, ranging from letters, photographs, boots, stuffed animals, sculptures, dog tags, college rings, a motorcycle, cigars, and helicopter pieces, the Post said.

The mementos are gathered and placed at the Museum Resource Center in suburban Maryland. The human cremains are kept in a large locked metal cabinet.

Park Service spokesman Mike Litterst said remains can no longer be added to the official “collections.”

"We're not permitted," Litterst said, per the Post. "And right now, we don't have an answer for what to do with these remains. But we do know that they won't become part of the collections."

Laura Anderson, curator for the Mall and Memorial Parks, said many of the containers often are not marked with a name.

"We don't have a way of knowing if it's even a Vietnam vet," Anderson told the Post. "Some of them could be other family members. They could be veterans from other wars ... We don't know."

Anderson said officials have been trying to come up with an idea of how the handle the cremated remains.

"Because we're not really equipped," Anderson told the Post. "I imagine it's a big decision — what you do with your loved one — especially if somebody is asking to be left here. You want to honor those wishes. But we're not allowed to accept them."

Janet Folkerts a curator at the parks service, said that wall is unique for many veterans.

"A lot of Vietnam veterans feel very connected to the memorial," Folkerts told the Post. "It speaks to them in a way that many other places in the country don't. So they would like to become part of it."